Falling For The Foster Brother
by ZEKI FOR LIFE
Summary: Deidara had been too young to remember that Sasori was in fact his foster brother, so he's always buried his true feelings he's always had for said foster brother. Rated M for possible later chapters. Rating may change. Slow updates.
1. Chapter 1

**I know I know, nya. I need serious help, that's not news to me xD I hope you guys will enjoy this regardless :)**

"Deidara, this is your new big brother Sasori." A blond haired woman said to a blond little boy, festering to a red haired boy at least five years older than the little boy.

The little boy waddled over to Sasori and smiled at him, tugging on the older boy's sleeve to get him to pick him up.

Sasori bent and hesitantly picked up the toddler. The blond wrapped his little arms around the redhead's neck, and that was the moment Sasori knew he needed to look out for his new little brother and cherish him.

 **So even though that was kind of a prologue, we're still going to call it chapter one, nya. I hope you guys will support this story, even though I will probably be slow about updating this one cuz I'm going to be picking my words very carefully, anyway bye.**


	2. Chapter 2

**Hey so I know it hasn't been that long since I last posted, nya... But I wanted to post this chapter :) also I hope you guys won't hate me after this chapter... I'm not even sure why I put something in here that I did... But I did.**

"Nii-chan, are you in here, hmmm?" An eight year old Deidara asked a thirteen year old Sasori, who, for some reason, had bolted into his room when they had been playing video games in the blond's room.

"Stop calling me that and go away Brat." Was the only reply the little blond received from the redhead. In the past few months Sasori had stopped wanting to be around the blond. This was very upsetting for said blond.

That's when it became difficult to breathe, like his chest was constricting his lungs as he wheezed and coughed. When he didn't stop, the redhead finally emerged from the dark room looking extremely worried and mildly terrified.

 **-Later after a trip to the doctor's office-**

"Why didn't you tell me about something this important?!" Sasori exploded angrily in the car.

"I didn't think it was information you could use." Deidara's mom answered, unaffected by the redhead's tone. To Sasori, it seemed like his foster mother had lost interest in him. Perhaps it was a good thing he had been adopted by another couple. He hoped Dei wouldn't be too upset about him leaving them.

Later when dinner was over and it was bedtime, Sasori went up to Deidara's room and slipped under the covers with him, wrapping his arms around the blond and pulling him close. He was actually going to miss this little brat.

"Nii-chan, why are you crying? What's wrong? I'm going to be fine, you heard what the doctor said." Deidara reassured his foster brother, wrapping his arms tightly around Sasori's neck. No matter what the little blond did, Sasori only cried harder. Starting to panic Dei placed a small clumsy kiss on the redhead's lips.

When the blond woke the next morn, it was to a cold and empty bed, in fact all evidence that Sasori had every lived there was gone. Over the years Deidara's mind blocked out all memories of the redhead's existence.

 **... Please don't hate meeeeeeeee, nyaaaaaa. I know I am a terrible person for doing that to our fav redhead and blond... But t-the story was headed in that direction a-and I can't control my own stories *looks around nervously and hope you guys buy that lie* anyway if you would be so kind as to leave a review (or even PM me) I will love you forever! *kamuis away***


	3. Chapter 3

**Okay so I know I updated this only four days ago, nya... But I felt terrible after what happened, so here's a new chapter!**

"Yo Blondie, the fuck you spacing out for?" Hidan, a foul-mouthed, silver haired, pink-purple eyed Jashinist, friend of Deidara's asked.

"Eh? What, yeah?" Deidara replied, being pulled from his daydreams of an oddly familiar redhead.

"Whatever man. This is why you're so fucking clumsy and run into things all the time." The blond just nodded, not hearing a single thing his friend had said, favoring the image of the attractive redhead in his brain. He was so spaced out he face planted in someone's back.

That someone turned around to ask if he was okay, but the question stuck in his throat and his mouth hung open. "D-Deidara?"

"Yes, hmmm?" The blond looked quite confused as he eyed the redhead suspiciously, noting that thus stranger looked extremely close to the red haired boy in his hazy dreams.

Deidara was pulled onto a loving embrace by this stranger, "I've been looking everywhere for you. I missed you so much." The redhead planted a small, sweet kiss on Deidara's lips, said blond froze, brain trying to register what was going on. People on the street stopping to stress at them, a few have blood gush from their noses.

 **So I know, it's super short, nya. But hey it makes me lol (yes I just made a jab at my own height, I apologize). But seriously, I did just update four days ago so be a little more grateful! And this is me, so it's obviously going to be short. Anyway please review cuz I need them to live like Kakuzu needs hearts xD**


	4. Chapter 4

**Okay so I apologize if this is sucks, nya. I haven't been feeling too well today... So yeah, anyway enjoy! Sorry for OOCness!**

 **Warning: ItaSasu is a thing in this fic... But they're only mentioned a little...**

Did pushed the redhead away, wiping his mouth with the back of his hand. Hidan was staring at them with a shocked look on his face. The redhead stroked the blond's cheek tenderly with a small smile gracing his lips.

"Oh and did I mention I'm your legal guardian now? I look forward to spending more time with you, Brat." Sasori whispered in Dei's ear, before giving it a little nibble.

That nickname unlocked a few memories of a red-haired boy, a boy Deidara used to call 'nii-chan'. The blond followed the redhead cautiously, head spinning with questions.

Before the blond could stop himself he asked one of them, "what's your name, hmmm?"

"My name is Sasori Akasuna, I'm 22 years old, I used to be your foster brother, we used to be very close. Are you telling me you don't remember me?" Sasori answered, a slight hurt tone in his voice, as he cranked the car.

"I'm sorry, I don't remember you. I vaguely remember a red-haired boy I used call 'nii-chan', but the boy in my memory is hazy, un. Sorry." The blond apologized, he really wished he remembered Sasori, but he didn't.

"You don't need to apologize, it was your late mother's fault for not adopting me and letting another couple do so, and for making me leave before you woke up. It was as if she didn't want you to think I even ever existed, I wasn't even allowed to leave a note." Sasori's hands tightened their grip on the steering wheel til his his knuckles turned white, overwhelming sadness welled up in Sasori's eyes, only to spill out seconds later, whenever he thought back on how he and Deidara parted it made him cry out of frustration, loneliness, and just general sadness.

These tears surprised the blond a bit, but he understood why the tears were now flowing freely out of the redhead's eyes. A memory played before the blond's eyes then. It was of the night before Sasori's departure, he had been crying, the blond had calmed him and they had held each other tight all through the night.

"Nii-chan, please stop crying, hmmm." Deidara said without thinking about what he had said, clamping a hand over his mouth when he did.

"Dei, are you not telling me something?" Sasori asked cautiously, drying his tears and looking at the blond at the blond, finding the flustered look on his face utterly adorable.

"My memory is coming back to me slowly, yeah." The blond responded, as they pulled up to a nice big house. "This is your house?"

"It's not just mine, eight other people live here, well sometimes more... But usually it'll just be us ten." The redhead replied as they walked up to the front door. When they entered the living room, a man that had green hair and half of his body tattooed black was sitting on he couch with a tall blur haired man. They nodded to Sasori as he and the blond approached.

"Kisame, Zetsu, this is Deidara, he's under my care. Dei these are two of my housemates. The one with blue hair is Kisame Hoshigaki, and the one with green hair is Zetsu Kushirou." Sasori introduced them, his arm around Deidara's waist, the others taking note of this and nodding.

The redhead and the blond continued onward to the dining room, there seated at the table was a blue-purple haired woman with orange eyes and a girl with really long red hair and brown eyes, "Konan, Kary-chan, thus is Deidara Iwa, he will be under my care from now on. Dei, the one with orange eyes is Konan Ame, she's a housemate and also Pein's wife and the one with red hair who looks like she's about to die from happiness is the daughter of the couple who adopted me, Kary. Fair warning both of them are fujoshis... So if we do stuff like this." Sasori paused and placed a quick kiss on Deidara's lips, the two girls squealed, "they'll act like total fangirls, just ignore it, you get used to it." The blond nodded, before getting pulled into a huge hug by both the girls.

They went into the kitchen and encountered two ravenettes making out, the shorter one being pressed up against the sink. Sasori cleared his throat and the talker one held up a finger as if to say 'hold on a moment, when the two did pull apart, Dei recognized one of them as his underclassmen, Sasuke Uchiha, and the other as Sasuke's older brother, Itachi.

"Good day, Iwa-kun." The older brother said politely, pushing his glasses up.

"Itachi, Sasuke, I take it you know Dei-chan?" Sasori asked, when he received two nods he continued, "well he is under my care." He tightened his grip around the blond's waist, a possessive hold.

Sasori guided Deidara down a hall and upstairs, then down another hallway, stopping at a door with two small signs by it, one that read : **_Sasori Akasuna_** and the other one; _**Deidara Iwa.**_ Just before they were about to enter two doors opened and out walked a super pale man with really long black hair from one and from the other came a talker Raven haired boy with an orange eye patch over his left eye.

"Perfect timing. Orochimaru, Obito, this is Deidara Iwa, he is under my care." Sasori introduced them, sending Obito a look that clearly stated 'do not touch my Dei-chan, you have Kakashi', "Dei-chan, the pale one is Orochimaru and the one with the eye patch is Obito Uchiha." With that the redhead and the blond entered their room. Deidara was immediately pinned up against the door, the redhead attacking his neck, leaving his mark on him.

 **Like I said not that great huh? I apologize, nya.**


	5. Chapter 5

**I know it's been a really long time since I last updated this fic, nya! I'm sorry! Anyway please enjoy this chapter!**

When it got around dinner time Sasori headed down stairs to get two bowls of whatever was for dinner. While the redhead was out, an orange haired guy with a multitude of facial piercings came into the room with a stoic expression on his face.

Gray-purple eyes fell on the blond, "I presume you're Deidara Iwa who is currently under Sasori's care? I am Pein Tendo, I was informed that you have already met my wife, Konan." The ginger held out a hand to shake, which Dei promptly did. Another man poked his head in the door at that moment, this one had half of his fave covered. "And this is Kakuzu, he's our treasurer, be careful not to overspend your allowance, trust me it's not a good idea." Pein paled more at the memory. The two left when a very possessive Sasori returned.

Immediately after they were finished eating, Sasori pulled Deidara close, that's when the blond's eyes caught something on the desk. Looking closer he saw that it was a picture frame. Sasori followed Dei's gaze and smiled, getting up, grabbing it, and bringing it to the blond who took it curiously from the redhead. As Deidara looked at the picture, any doubt in his mind that Sasori was who he said he was diminished, for there, with smiles on their faces and arms around each other in a sort of one-armed-hug, was a younger Sasori and a younger Deidara. Tears prickled in the back of the blond's eyes, the rest of his memories flooding back into his mind, and he felt oddly lonely and warm all at once.

What broke Deidara out of his reverie was Sasori leaving little kisses all over the blond's face and him whispering soft reassuring words in his ear. Deidara snuggled closer on the bed to Sasori, wanting to be even closer to the red haired foster brother he had fallen in love with at a young age.

 _Wait, love?! Well I suppose that is typically what you would call this feeling, hmmm..._ Dei felt his cheeks heating up at his thoughts, his cheeking and entire face, for that matter, heating up further when he heard and felt the redhead chuckling, only then did he realize he had, in fact, said them out loud.

"Don't worry, I love you too, Brat. Good night." Sasori said teasingly and planted a kiss on top of the blond's head.

"Good night, nii-chan." Deidara replied in a cute tone, knowing it would make the redhead have to forcibly stop himself from pouncing on the blond, and hoping it would torment him all night.

They fell asleep not long after, safe and warm, both finding each other's natural body heat the most comforting thing in the world, the best temperature for being cozy and for for sleeping.

The next day when Dei woke he was in Sasori's arms, secure and comfortable. Looking up Deidara saw the redhead looking at him tenderly with a soft smile on his face.

"Good morning, mon amour. I hope you slept well." The red haired man said, softly stroking the blond's long locks.

"... 'ning nii-chan *yawn* yeah I slept pretty good." The blond replied, snuggling closer to Sasori. The latter chuckled and soon the two fell back asleep.

When two o'clock rolled around, Konan was sent to the blond and redhead's room to make sure they weren't trying to kill each other (or Sasori wasn't making Deidara do anything he didn't want to do). The sight she beheld when she entered the room made her have to clamp a hand over her mouth to stop her fujoshi squealing, for there, cuddling together with contented smiles on their faces like a cute scene out of a Boys Love fanfiction **(a/n: *jabs everyone in the ribs with my elbow while giggling*)** , were Sasori and Deidara in each others arms. Konan got out her phone and snapped a whole bunch of pictures from different angles and sent only the best ones to Kary who would, no doubt, save every one of them and probably have one as the background to her phone. Konan left the room shortly after to go report to Pein that 'everything was just peachy!' Probably with an ecstatic smile on her face that would later cause her husband to be slightly concerned.

When the foster brother turned, dare I say it?, lovers awoke from their long slumber and went down stairs, they were a little confused as to why Konan and Kary kept glancing at them, giggling, talking amongst themselves and then glancing at them again. Finally Sasori and Dei decided it was just the way fujoshis are.

Deidara did catch a little of their conversation, "I have to disagree with you Kary-chan, Deidara and Sasori are obviously both sekes, you know half seme and half uke, meaning they take turns being uke and seme." To which the reply was Kary shaking g her head while insisting, "I believe Sasori would make a better seme, to me Dei is more of an uke." Deidara kept these words 'seme' and 'uke' in his mind so he could research them later.

... And when he did he wished he hadn't have with the redhead with him, nay while he was sitting on Sasori's lap and leaning back into his chest.

Deidara got out his phone and looked up both 'seme' and 'uke'. When he found the definitions he blushed bright red.

"Why the hell are you looking up Boys Love terms, Brat?" Sasori asked intrigued and confused all at once, pulling said blond closer against his chest.

"Cause... Cause Kary-chan and Konan were talking about it..." Deidara trailed off embarrassedly hiding his face in his hands.

"Go on, what were they saying?" Sasori asked with a slightly teasing tone In his voice, burying his face in the back of the blond's neck, inhaling deeply.

The redhead had to strain to hear what Dei mumbled next, "Konan said t-that we're both sekes, half seme and half uke... And Kary-chan *sighs* Kary-chan said that you're definitely the seme and I seem to be more like an uke, un." Dei seemed quite... What's the word? Embarrassed? Yeah that's the word! He seemed quite embarrassed about being very uke-like, so, Sasori being the way he is, decided to sort of tease the other boy.

"I always knew Kary-chan had good intuition but she's out done herself this time! Oh, come on Dei-chan you know you like being an uke~ wow that is some blush you've got there, hee hee." Sasori licked the shell of Dei's crimson blush covered ear and bit it, earning a sound of pleasure from Deidara, who, upon realizing the sound he had just made, clamped a hand over his mouth and blushed harder, which resulted in a delighted chuckle from behind him. Deidara turned his head slightly and glared at the redhead, who in return just kissed his cheek and mumbled something in French.

 **I hope you guys liked this! And I know I wrote Dei being embarrassed about being an uke... But don't be embarrassed Dei-chan, I'm an uke too, but I'm pretty happy about that! (According to the quiz on semeuke I'm a mix of an innocent uke and a clueless uke. And them according to my zodiac (which is Pieces) I'm an innocent uke). I hope you wonderful readers have a lovely day! Please continue to support this story even if it takes awhile!**


	6. Chapter 6

**Hey there my awesome readers, nya! I hope you guys enjoy this new chapter!**

There was a loud, sharp knock on Sasori and Deidara's room early in the morning about a month after the redhead had become Dei's guardian. The man at the door was the blond's friend, Hidan. The redhead opened the door with his other arm around the blond's waist.

The silver haired boy gawked at them for a moment and then started speaking, "look Red, I don't know who the fuck you think you are but you can't go around kidnappin' teen boys and Blondie what the fuck man?! Why the fuck are ya lettin' him have his arm around your waist?!"

When Deidara finished explaining (almost) everything to him, Hidan just shook his head and said, "dude, if this makes you happy then I support ya. And Red the second you make him cry I swear to Jashin you will pay dearly!" He turned to leave just as Kakuzu happened to walk by. Hidan followed him into a room and yelli.g and other loud noises were ensued.

 **I know short chapter right? Well the reason for that being cuz there will probably be only one more chapter left :)**


	7. Chapter 7

**Hey my dearest readers, this is probably my last chapter for this fic, nya.**

 **Warning: this chapter contains (probably) not well written smut scene (I'm quite shy when it comes to writing this sort of thing) so if that's not something you want to read, just read the beginning of it and then stop :) oh! And a small mention that suggests ItaSasu!**

 **-A Year Later-**

It was the blond's 18th birthday and the redhead had a surprise present for him, that he would get as soon as he walked down stairs in the morning.

There was a blond haired blue eyed girl standing at the bottom of the staircase. She was like a female copy of Deidara, the same height and everything. She looked extremely nervous and slightly worried. Dei was a little confused as to who she was and why she looked exactly like him, so he turned to his lover and asked who she was in a quiet whisper.

"Deidara, this is your twin sister Ruihime. You guys were separated at birth cause she was frail and a girl. You know the more I find out about your mother, the more I can't help but hate her." Sasori answered. By now they were standing in front of Ruihime, who bowed her head under their gazes, feeling rather shy and a little scared.

It was only a moment of standing there before Dei embraced the other blond tightly, as though his very life depended on how tight he hugged her.

Tears were shed, many more hugs were shared and Sasori revealed that Ruihime would be living with them from then on, which prompted both twins to tackle hug him and say thanks. When the three walked into the living room everyone jumped out and wished the twins a happy birthday.

Later that night after cake and presents, Ruihime had to go home and pack, Itachi and Sasuke were alone in the kitchen and were taking an awfully long time washing the dishes **(a/n: ;) if you know what I mean)** , Kakuzu and Hidan hadn't been seen in awhile, Kakashi and Obito were sitting very close near each other casting sheepish glances to one another every now and then, Sasori and Deidara were cuddling together happily, and Konan and Kary were trying hard to contain their fangirl squeals at just how much cute real life yaoi was going on. At some point Konan cracked, squealing and giggling very loudly, while Kary, still watching the cute SasoDei adorableness, was doing a better job at keeping quiet, but just barely.

When midnight rolled around Sasori stopped a sleeping Deidara up in his arms bridalstyle, Konan, being as devoted and a little too open about her fujoshiness, took a ton of pictures (that she would later share with Kary). As Sasori was trying to open the door and still hold the blond's without waking, Deidara huffed impatiently and opened the door for the redhead, then went back to pretending to be asleep.

"Well I always knew you were childish, but honestly Brat pretending to be asleep? You've out done yourself this time." Sasori teased, when they entered the room. The blond showed little to no signs of stirring, so the redhead tossed him on the bed, quickly sitting on top of him and started tickling Deidara's sides while simultaneously kissing his neck. In no time at all the younger was begging Sasori to stop while laughing uncontrollably.

When the redhead did relent and they caught their breath, Sasori stared into Dei's sky blue eye as Deidara stared into muddy brown ones. As though their lips were magnets drawn to one another they connected in a sweet gentle press at first, then it became more heated. Sasori nibbled on Deidara's bottom lip, asking politely for entrance which was granted without a second thought. Their mouths mashed together hungrily and their tongues fought for dominance. While their mouths were preoccupied, their hands explored every inch of skin they could, pulling up one another's shirts to feel more. At some point Sasori's hands went lower and one slipped into the waistband of the blond's boxers, and did not realize what he had unconsciously done until Dei slipped his hand into Sasori's boxers and gave the redhead's fully erect cock a pump. Sasori let out a low moan that was more like a groan. The two had done this sort of thing before, so they were pretty accustomed to what the other was comfortable with, of course they had never gone all the way since Deidara was always too embarrassed and Sasori was considerate. So the blond's next words both surprised and stunned Sasori.

"Sasori... I-I want you to be inside me, yeah! It's my eighteenth birthday after all, that's what you were waiting for right? For me to be legally an adult so that way if Konan is secretly recording us and the police search her stuff you wouldn't go to prison." Deidara wore a light blush on his cheeks as well as a slightly teasing smile, causing Sasori to laugh.

"How did you know!? I thought I hid it so well! But seriously Brat, I was actually waiting for you be more comfortable, you were always quite embarrassed when it came to the subject of sex, so I didn't want to pressure you if you weren't ready. So are you sure you want to do this? Cause I can wait a few more years if I have to. Is this really what you want Dei, cause once we start I don't think I can stop... Of course I would try to for you... But I don't know how well-" before Sasori could finish, Deidara shut him up with a kiss.

"I'm sure Sasori."

"Very well then." And with that the redhead promptly undressed both of them and put three fingers to the blond's lips a silent command for him to coat them in his saliva. When Sasori deemed them to be wet enough he trailed them down to Dei's entrance, pushing one in immediately and, hearing no protest from the blond, pushed in the second, already beginning to stretch his lover. When the two were bearable he pushed in the third and finally one, scissoring them and thrusting them in and out while all the while searching for that wonderful spot that would drive Deidara over the edge of ecstasy. He knew he had found it when Dei threw his head back and emitted a loud moan, asking for Sasori to 'do that again, yeah' to which the redhead obediently stroked the blond's sweet spot again.

Sasori, being at his limit, pulled his fingers out and pushed something MUCH bigger into Deidara's ready and waiting entrance, inch by agonizing inch. When he was fully sheathed he waited for the blond to adjust to his length, sucking and nibbling on Deidara's neck.

"You can move now, Danna." The blond panted out after awhile, giving the other man a new nickname. Sasori obliged, pulling mostly out before thrusting back in and hitting Deidara's prostate everytime.

"This -hah- this isn't the first time you've done something like this i-is it, hmmm?" Deidara asked while Sasori increased the power and speed of his thrusts, causing the blond to not be able to think of anything but how good it felt and to moan wantonly.

"Only with one other person I dated, but I wish I had waited." Was Sasori's grunted response.

The blond felt more and more heat building in his abdomen and was about to warn the redhead when he felt Sasori paying attention to his neglected member, causing his moans to increase in both pitch and frequency. Before long he came all over Sasori's hand and their chests, while he was catching his breath he felt Sasori release his hot sticky seed deep inside him, before collapsing on top of him without pulling out.

"Danna again, un!" Deidara said, mimicking what he used to say when he was younger and he wanted Sasori to do something again, only changing 'onii-chan' to 'danna'. Sasori chuckled, but did as he was requested.

And thus the night ensued with more moans, some cuddling and Deidara being marked many times by Sasori.

 **Okay so this was most likely the last chapter, but I might do one more... I'm not entirely sure thiugh... For all you who have supported this fic thus far, I thank thee!**


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